JPS608194A - Excessive letdown-rate alarm device for rotor aircraft - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to ground approach gf warning systems, and more particularly, to detecting the rate of descent of an aircraft, such as a helicopter, relative to the altitude at which the aircraft is traveling. A device for giving a warning to the operator of a rotating aircraft, such as a helicopter, in case of excessive rotation I1.
Regarding. Such warnings are particularly useful during the approach and landing phases of an aircraft entrainment.

Devices are already known that give special warnings to the pilots of aircraft in the event that the aircraft descends in an excessively heavy manner during landing. Examples of these devices are disclosed in U.S. Pat.
ll, No. 338, No. 39 Gua gθg, No. 395g, 2
No. 79 and No. 11.2/! iJ, 3Q specification.

Top grip: All devices disclosed in I'l provide a warning to the pilot when the aircraft's descent rate exceeds a predetermined safe speed determined by the aircraft's altitude above the ground. Although they perform the basic function of warning or warning against aircraft, these devices operate in conjunction with transport aircraft, particularly large turbine-powered aircraft of the type that are in service on commercial air routes. It is designed to. However, because rotary-wing aircraft are significantly more maneuverable than transport aircraft, warning systems designed for transport aircraft cannot be used on rotorcraft unless an unsafe condition exists. However, it tends to give false alarms or harmful alarms. In such a case, pilot i
1. As a result, there is a tendency to ignore the alarm given by such a warning device, and the warning device is therefore ineffective. It is described in IO No. Specification 8.

This device monitors the rate of descent of the aircraft as determined by the rate of radio altitude change and generates an alarm if the rate of descent is excessive for the altitude at which the aircraft is flying. This warning system is much more suitable for use in rotorcraft than warning systems designed for transport aircraft.

However, the system described in US Pat. No. 729.38140 is a relatively complex system that adjusts the altitude at which the warning is issued as a function of the forward speed of the aircraft. It is also believed that the devices disclosed in the above-mentioned patents are designed for use in non-tactical aircraft operations. Therefore, when used in aircraft used for tactical maneuvers, it may exhibit a tendency to generate false or harmful alarms.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide a ground proximity warning system which overcomes many of the disadvantages of conventional warning systems.

Another object of the invention is to provide a warning to an operator of a rotary wing aircraft when the rate of descent of the rotorcraft is excessive relative to the ground altitude signal over which the aircraft is flying.

Yet another object of the present invention is to select warning criteria to be consistent with operating procedures used in rotorcraft to alert pilots when the rate of descent of the rotorcraft is dangerously high. It is another object of the present invention to provide a ground proximity warning system for alerting people in this regard. To provide a warning device for use in a rotary wing aircraft that generates a warning but hardly generates false alarms or harmful warnings even when used in aircraft with high startup performance.

Another object of the invention is to alert the operator to an excessive rate of descent if the rate of descent of the rotorcraft exceeds a first predetermined value which is a function of the aircraft's altitude above the ground. To provide a cargo information device for a rotary-wing aircraft, which generates a first eaves signal for a rotary-wing aircraft, and generates a second eaves signal of Ycil- when a maximum permissible descent rate is substantially exceeded. be.

A further object of the invention is that the criteria used to determine whether a warning should be generated is whether the aircraft is flying the tactical leg of its mission or the non-tactical leg. The object of the present invention is to provide a ground proximity warning system which is particularly usable in rotary wing aircraft such as tactical helicopters.

SUMMARY OF THE INVENTION In summary, in accordance with a preferred embodiment of the present invention, the ground altitude and rate of descent of a rotorcraft is monitored so that the rate of descent is determined to be safe and predetermined relative to the radio altitude at which the aircraft is flying. A device is provided which generates a first audible alarm 'fc if a limit is exceeded. If this rate of descent exceeds the predetermined safety limit by a predetermined margin, another audio tone of λth is generated to inform the pilot of this particularly dangerous flight condition. . The criteria for generating these warnings is to minimize harmful warnings when the aircraft is flying a tactical mission zone, while still allowing the pilot to land the aircraft by rotation. The warning criteria are modified to optimize the warning criteria for the maneuvers or operations normally conducted during the tactical mission segment, so that adequate warning is provided.

The above-mentioned objects and other objects and advantages of the present invention will be readily understood from a consideration of the following detailed description taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference is now made to the drawings, and in particular to FIG. 1, in which one embodiment of a ground proximity warning system for rotorcraft according to the present invention is indicated generally by the reference numeral 10. ing. This system or apparatus lθ according to the invention is shown in a logic block diagram in FIG. 1 as consisting of a series of gates, comparators, and the like for convenience of explanation, however, the actual implementation of the logic It is to be understood that this is possible in other ways than that shown in FIG. 1 and may be implemented using a variety of digital and analog techniques. The signals used in the system or equipment described herein may include radio altitude signals and barometric altitude rate signals, signals indicative of tactical or operational missions, such as signals derived from tactical mission switches, and various other useful signals. including. Depending on the type of aircraft in which the warning system is installed, the signals shown in Figure 1 may be
．． 2. Pressure change rate circuit/<Z, radio altimeter/fxf' as well as a tactical mission switch that indicates whether the aircraft is in tactical mode operation or non-java mode operation.
14 can be obtained from individual instruments such as religious elements. Alternatively, in some modern aircraft these signals can be obtained from a digital gutter busbar.

As already mentioned, in the system or apparatus according to the invention, the aircraft's altitude above the ground and the rate of descent (radio altitude change rate can be used, but preferably the barometric altimeter rate of descent) are compared to determine whether the aircraft is flying. If the rate of descent is excessive for the current altitude, a warning is generated. This comparison function is implemented by a mode comparator/gVC.

The comparator/g6・Well, in this example, the altimeter 16
The radio wave altitude signal from the altitude change circuit and the barometer altitude change signal from the rate-of-change circuit/gugara are compared based on three different criteria. In the illustrated embodiment, these three different criteria are set by three parts of comparator/g. These parts include a descent rate comparator, 20, a lift comparator, 2.
2 and a tactical drop rate comparator. All these parts or comparators, 2.2. ．． 2g is shown as part of comparator/g for convenience of explanation, however, three separate comparators could alternatively be used. Also, comparators, 20°-1 and 217. The above designations given to the above are merely for convenience of explanation to indicate the types of audible alarms activated by these various comparators and to correlate these various comparators with the specific alarm criteria shown in FIGS. 2 and 3. It goes without saying that other names could be given to these three comparators, as chosen for this purpose.

The output of each of the comparators 20, 2 and 2 is applied to three antagonists, 2A, 2g and 300A forces, respectively. These AND gates, 2A, 7g and 3θ, will be enabled under different conditions. ANDGATE J6 and 2g are prohibited by tactical prohibition signals during tactical maneuvers. This tactical prohibition signal may be e.g.
It can be obtained from discrete circuit elements such as tactical mission switches or weapons loading switches. Conversely, AND gate 30 is enabled by the tactical inhibit signal during the tactical maneuver phase, so that AND gates, 2l and 2g control the generation of Wr signals during the non-tactical flight phase, while AND gate 3o It will control the generation of alarms during War WG maneuvers.

Furthermore, three AND gates, 26. ．． 2g and 30
are all inhibited by the signal from the 10-foot comparator 3.2. The comparator compares the radio altitude signal from the radio altimeter/B with a reference signal representing an altitude of 10 feet above the ground and determines the AND gate, mA, Jg, and 3θ when the aircraft's altitude above the ground is less than 10 feet. prohibition, thereby serving to suppress harmful alarms to a minimum.

Additionally, all three gates are disabled by the BARORATE VALID signal in the event of a failure in the air altimeter or barometric altitude change circuit, and in the event of a failure in the radio altimeter or other instruments. When it occurs, the master inhibit signal (MASTERINHIBIT)
Bans ANDGATE-Otsu, 2g and 30.

Assuming that the aircraft is flying at a ground code greater than IO feet, and gates 24, . Assuming that neither 2g nor 3o is prohibited by Ike's power against the andgate, the antgame)
, 2A, , 2 & and 30 are comparators, respectively. , -, and 1, and if any of the three alarm criteria mentioned above is violated, a related 14 alarm will be generated.

For example, if the aircraft were flying in non-tactical flight mode, gates 26 and 2g would be enabled and gate 30 would be inhibited. Under these conditions, if the combination of descent rate and ground altitude is such that the alarm standard set by the descent rate comparator UO is exceeded, the descent rate comparator λθ is set by the AND gate 2. Applying an enable signal to the ant gate, which causes the ant gate to reduce the rate of descent (
5INK RATE) Apply an alarm activation signal to the signal generator 3da. Preferably, the fall rate signal generator jF is a digital audio generator that generates a specific audio alarm in response to an alarm activation signal from the AND gate, 26. The specific sound tube layer signal is then directly or indirectly applied to a transducer or transducer, such as an earphone or loudspeaker 36. Warnings should be specific to inform the pilot of the specific condition that caused the axis to occur, and audio expressions [rate of descent] should be used to notify the pilot of the problem. (SINK RAT
E) J was found to be particularly useful.

If the relationship between the rate of descent of the aircraft and the altitude above the ground is such that the alarm criterion set by the pull comparator unit 2 is exceeded, then the pull comparator 2.2 ) Apply the J&LC enable signal. Typically, exceeding the warning criteria set by the pull-up comparator, yuko, represents a more dangerous flight condition compared to exceeding the criteria set by the rate of descent comparator, 2o. . Therefore, a more urgent alert is given under such circumstances.

In the illustrated embodiment, this more urgent N-signal is transmitted by a digital audio generator (WHOOP-WHOOP PtJLL-1), which is preferably a digital voice generator.
JP), 7 g. This generator Jg
may be separate from the generator 3, or alternatively preferably integrated into the same unit.

Generator 3gB is controlled by a gate, zglF-, which applies a signal to generator 3g via delay circuit tlo. Therefore, the alarm generated by generator JgK is
．． Occurs a short time after the alarm criterion set by 2 has been exceeded.

It is preferable that the delay time caused by the delay circuit θ is about 1, or S scale. According to this value, it has been found that it is possible to suppress harmful alarms to the minimum limit without excessively shortening the alarm time. Alarm priority is Generator 3
This is selected because hierarchical generation by the generator 39 is prohibited upon generation of an alarm by g.

When the aircraft is in the tactical maneuver phase, the gate roll and
2g is disabled, while AND gate 30 is enabled by a tactical inhibit signal.

As a result, the ANDGATE 3θ is a tactical drop rate comparator, 2u
The comparator, 241, provides a signal to gate 30Vc when a criterion set by it is exceeded. As a result, the gate 3θ generates the alarm activation f word and the descent rate (5INKRATE) generator, ? 4NC
In this way, the reason why the ``1 Descent Rate'' alarm is selected instead of the ``Woo Woo Sound Raise''@ warning is that the latter will generate a 5 INKRATE warning. It is a more specific indication of
This is because there is less chance of confusing the pilot during tactical maneuvers.

The specific relationship between altitude above ground and rate of descent required to generate a 1/C11 signal during non-tactical modes of operation is illustrated in Figure 1. The graph in Figure 1 is one 1! Shows a stored envelope or envelope with i-signal boundaries. 1st
The alarm boundary SO includes two line segments S and S, and the inner alarm boundary 40 includes a pair of line segments 62 and 6. The outer boundary SO is the backdoor expression “SINKRATE” that is generated when the boundary SO is violated.
J may be named a caution boundary because it alerts the pilot to a specific existing dangerous situation. Boundary 10, on the other hand, is such that if this boundary is violated, a more dangerous flight condition will be displayed than if boundary jo is violated.
This could be called the alarm boundary. The power that came out; that's why it's said that an even more urgent report like "Woo-woo sound" will be issued when the f%M boundary 10 becomes 41-1. reactor.

The shape of the boundaries 50 and 60, V, 1, was chosen to generate few harmful alarms (and to provide a sufficiently adequate warning to the operator). It turns out that it is desirable to create a stage report curve with λ different slopes in L.
] This would allow the pilot to have sufficient control at normal flight altitudes without producing false or harmful alarms during low-altitude operations, as is always done during normal landing approaches and towing. If the alarm time is given, an alarm system with good performance can be obtained. Kerr has found that a suitable equation for defining the line segment 3.2 that exceeds the rate of descent of S0θ feet per minute can be expressed as follows.

HWARN = / go feet 10,, 2733
×) 1■ In the above formula, HWARNj represents the altitude in feet at which the warning will be issued, and H1 represents the rate of descent in feet and 7 minutes.

A line segment that represents a rate of descent less than 300y per minute! i Hiro is determined by the following formula (7).

HWARN""9.20 ft. 0.76A/,X
The formula for Hb line segment A2 is expressed as follows.

The formula for HWARN = / /θft 10, /gXHb line segment 6g is as follows: 0. is expressed in

HWAR seal = -2,2'lθ fee) (7,/4XH
Segment B intersects line Sg at a radio altitude of approximately 230 feet, and line segment Otoyu intersects line segment 4H at a radio altitude of approximately 14θ feet.

To minimize harmful alarms, all alarms should be prohibited below radio altitudes of 10 feet.

The H-signal curve typically extends to the radio altitude range limit of 500 feet. The warning wrapper required to generate a warning during the tactical maneuver mode is graphically represented in FIG. The warning boundaries shown in FIG. 3 are drawn based on the aircraft reaching its maximum possible rate of descent that can be recovered by rotation in the event of a failure of the aircraft engine or rotor system.

In the event of a failure of one or more of the elements driving the main rotor, an aircraft such as a helicopter can be brought to a safe landing by a process called rotation, which is similar to glide in fixed-state aircraft. These are the seven characteristics of rotorcraft such as helicopters. In this rotation mode, the pitch of the main rotor is adjusted to rapidly rotate the main rotor as the aircraft descends, thereby generating main rotation g[kinetic energy. This kinetic energy is later used to slow the aircraft's descent during ground approach.

Typically, during the energy accumulation phase of rotation, the helicopter blades are initially maintained at a relatively low pinch angle to accelerate the rotor while the aircraft is still at relatively high altitude. As the aircraft approaches the ground, it releases stored energy by increasing the pitch of the rotor blades, thereby slowing the aircraft's descent prior to touchdown.

Unfortunately, the rotation mode described above is dangerous for the following reasons. That is, relatively high rates of descent can be reached during the energy storage phase and the amount of kinetic energy that can be stored in the rotor is limited. As a result,
It may occur that the pilot reaches such a rate of descent that the limited energy stored in the rotor cannot reduce the rate of descent sufficiently to allow a safe landing. obtain.

The curve shown in Figure 3 defines the maximum rate of descent that will allow a safe landing by rotation as a function of altitude and should be used for one purpose only. As a primary purpose, this curve allows the aircraft to land safely on its axis if damaged by enemy fire during tactical maneuver mode or by stresses encountered during combat maneuvers. It helps the VC pilot maintain a relationship between rate of descent and altitude above ground level.

First, the de-levelling system assists the pilot by issuing a warning whenever the rate of descent becomes excessive once rotation mode is initiated. Note that the curve in Figure 3 is 5iko
It is optimized for rski CHk J series helicopters, but can also be used on other similar helicopters. However, if it were to be used with helicopters having significantly different flight and operational characteristics, certain modifications would be required.

In the flywheel illustrated in FIG. 3, an alarm is generated whenever the aircraft is above ground/theta feet and the alarm boundary defined by curve 70 is violated. As previously discussed in the previous VC, the warning boundary 70 defines the maximum rate of descent that will allow the aircraft to recover as a function of altitude above the ground using the following equation: The equation for this boundary 7θ is expressed as follows.

HWARN= -/ g e, A feet 10, / & 9
It goes without saying that numerous modifications and variations of the present invention are possible in light of the teachings set forth above. It is therefore to be understood that, within the scope of the invention, the invention may be practiced otherwise than the specific embodiments described above.

[Brief explanation of the drawing]

FIG. 1 is a logical block diagram of a warning system according to the present invention; FIG. Figure 3 is a diagram graphically illustrating the rate of descent required to generate a warning as a function of radio altitude when the device is operating in tactical operation mode. Yes. 10...Ground approach front layer system, 7.2...Barometric altimeter, /G...Ki LE altitude change rate circuit, /&...Radio altimeter, 1g...Mode comparator, -〇...Descent rate Comparator 1.2
−・ψ pull-up comparator, −g・・tactical drop comparator, +26
．． +2g, Jθ-・anchor, 3g・・1 descent rate generator, 36・・loudspeaker, 3g・・woowoo sound raising alarm generator, Gθ・・delay circuit, SθI60.70・・′N
information boundary.

Claims (1)

[Claims] /) For a rotary aircraft of a rotatable type 0) If l
. In the apparatus, receiving means receives a signal representing an altitude above ground of the aircraft and a rate of descent of the heavy aircraft; and warning means for generating a V'C warning when the aircraft is approaching a point where it cannot land. , 2) means for providing a signal representative of the aircraft's altitude above the ground;
2. A warning system for a rotorcraft according to claim 1, further comprising means coupled to the receiving means for providing a signal indicative of the rate of descent of the aircraft. 3) A warning system for a rotating aircraft according to claim 1, wherein the means for providing a ground altitude signal comprises a 4-wave altitude signal. (i) the alarm generating means responds to the altitude and descent rate signals;
At an altitude of about IO feet above the ground, the rate of descent is about 3j
means for generating seven alarms when the rate of descent exceeds about 3 SOθ feet per minute at a height I04 of about 3jθ feet above ground level; A warning system for a rotorcraft according to claim 1. 9. In a warning system for informing an operator of a tactical rotorcraft of unsafe flight conditions during tactical and non-tactical flight phases, in response to a signal representative of the altitude and rate of descent of said aircraft, said aircraft when the aircraft is flying in a non-tactical flight phase, an alert is generated if the rate of descent of the aircraft exceeds a predetermined rate of descent determined by a primary criterion for the altitude at which the aircraft is flying; for a rotary-wing aircraft, comprising means for generating a warning for the aircraft, and means for, in response to a flight phase of the aircraft, switching from a VC first reference to another first reference when the aircraft enters a tactical flight phase. alarm device. [l] The first criterion is for the rotary-wing aircraft described in claim Alarm device. 7) A warning device for warning an operator of a rotary-wing aircraft of an unsafe flight condition, including receiving means for receiving a signal representing the aircraft's altitude above the ground and the aircraft's descent rate; Occurs when flying above a predetermined altitude above the ground and has a rate of descent less than approximately 7,300 feet per minute, and when the altitude above the ground falls below the service altitude defined by the following formula: means for generating one alarm, where HWARN represents the altitude in feet at which the warning is generated, and HWARN represents the rate of descent in feet 7 minutes, and HWARN is higher than /300 feet per minute. If the rate of descent is
RN=-/g O feet 10, 2 J, 3 x Hb
Warning device for a rotorcraft comprising means for generating a warning upon descending below a warning altitude (HWARN) defined by HWARN. g) means for generating a first separate warning if the rate of descent is less than 100 ft/min when the aircraft descends below a warning altitude (HWARN) defined by the following formula: When descends below the warning altitude (HWARN) given by the following formula % formula %, the rate of descent is /! Claim vJ comprising means for generating an alarm when the speed exceeds i00 feet/min.
Warning device for a rotorcraft according to paragraph J7. q) The alarm device according to claim 3, wherein the altitude (HWARN) is a radio wave altitude, and Hb is a pressure altitude drop rate. 10) Warning device a0 for a rotorcraft according to claim 7, wherein the warning means comprises means for generating a first and a first audio warning.